C# test suite PoC by dacharyc · Pull Request #50 · mongodb/docs-code-examples

dacharyc · 2025-06-27T22:04:04Z

This PR adds a proof-of-concept C# test suite, following a similar structure to our other test suites.

This PoC tests the C# code examples on the Group and Total Data page.

MongoCaleb · 2025-06-30T20:37:45Z

usage-examples/csharp/driver/Examples/Aggregation/GroupTotal.cs

+
+    public void SeedData()
+    {
+        DotNetEnv.Env.TraversePath().Load();


I'm not a fan of using third-party tools, like DotNetEnv. I mean, it's great, but it's also one more dependency to keep tabs on. IIRC, in the existing test solution, we just read the file?

MongoCaleb · 2025-06-30T20:40:22Z

usage-examples/csharp/driver/Examples/Aggregation/GroupTotal.cs

+        // :uncomment-end:
+        // :snippet-end:
+        var client = new MongoClient(uri);
+        _aggDB = client.GetDatabase("agg_tutorials_db");


Idiomatic C# doesn't use _variable except in private getters/setters. Also, it's recommended that variables names are more explicit. In this case, I'd go with sampleDatabase or aggregationDatabase or similar.

same as all cases below this, too.

FWIW, the DB name comes from an existing code example. This is the DB name used across 5 pages across all of the programming languages, so changing it would be non-trivial and out of scope of this PR.

MongoCaleb · 2025-06-30T20:41:42Z

usage-examples/csharp/driver/Examples/Aggregation/GroupTotal.cs

+    public List<BsonDocument> PerformAggregation()
+    {
+        DotNetEnv.Env.TraversePath().Load();
+        string uri = DotNetEnv.Env.GetString("CONNECTION_STRING", "Env variable not found. Verify you have a .env file with a valid connection string.");


usually use var instead of string unless it's not clear what is being returned.

MongoCaleb · 2025-06-30T20:41:53Z

usage-examples/csharp/driver/Examples/Aggregation/GroupTotal.cs

+    public void SeedData()
+    {
+        DotNetEnv.Env.TraversePath().Load();
+        string uri = DotNetEnv.Env.GetString("CONNECTION_STRING", "Env variable not found. Verify you have a .env file with a valid connection string.");


usually use var instead of string unless it's not clear what is being returned.

MongoCaleb · 2025-06-30T20:42:52Z

usage-examples/csharp/driver/Examples/Aggregation/GroupTotalOutput.txt

@@ -0,0 +1,3 @@
+{ "CustomerId" : "oranieri@warmmail.com", "FirstPurchaseDate" : { "$date" : "2020-01-01T08:25:37Z" }, "TotalValue" : 63, "TotalOrders" : 1, "Orders" : [{ "OrderDate" : { "$date" : "2020-01-01T08:25:37Z" }, "Value" : 63 }] }


I don't know how this is used...should it be pretty-formatted?

Just pulling it in from the docs page where it's currently used. We don't pretty format it there, so I kept the existing formatting. (Presumably because pretty formatting it would make it much longer, and that would take up a lot of real estate on the page, but I'm making an assumption.)

MongoCaleb · 2025-06-30T20:44:17Z

usage-examples/csharp/driver/README.md

+   27017/tcp -> [::]:27017
+   ```
+
+### Create a .env file


Depending on my initial comment about using the 3-party library, this may change.

Oh, good point. I've changed the way I'm loading this so it's now being used properly to load .env vars at the beginning of the test suite run instead of having to read the file over and over again in various places to get the vars. I think the third-party lib is justifiable for env var management, and according to NuGet, this one has 12 million users. I think it's probably safe in this case to assume it's reasonably maintained.

MongoCaleb · 2025-06-30T20:46:50Z

usage-examples/csharp/driver/Tests/GroupTotalTest.cs

+    [Test]
+    public void TestOutputMatchesDocs()
+    {
+        var obj = new GroupTotal();


I'd have to run this to be sure, but I think you can make obj global, and then, because you are calling new GroupTotal() in the setup, you don't need to do it here. In fact, I think your setup isn't actually doing anything.
Also, please rename obj to something meaningful. A new developer will have no idea what it is.

MongoCaleb · 2025-06-30T20:47:17Z

usage-examples/csharp/driver/Tests/GroupTotalTest.cs

+        var results = obj.PerformAggregation();
+
+        DotNetEnv.Env.TraversePath().Load();
+        string solutionRoot = DotNetEnv.Env.GetString("SOLUTION_ROOT", "Env variable not found. Verify you have a .env file with a valid connection string.");


consider changing all string = to var =

MongoCaleb · 2025-06-30T20:50:01Z

usage-examples/csharp/driver/Tests/GroupTotalTest.cs

+        string fullPath = Path.Combine(solutionRoot, outputLocation);
+        var fileData = TestUtils.ReadBsonDocumentsFromFile(fullPath);
+
+        Assert.That(results.Count, Is.EqualTo(fileData.Length), "Result count does not match output example length.");


Consider adding the variables to the output, like:
`$"The result count {results.Count} does not match the expected count of {fileData.Length}."

MongoCaleb · 2025-06-30T20:50:23Z

usage-examples/csharp/driver/Tests/GroupTotalTest.cs

+        Assert.That(results.Count, Is.EqualTo(fileData.Length), "Result count does not match output example length.");
+        for (int i = 0; i < fileData.Length; i++)  
+        {  
+            Assert.That(fileData[i], Is.EqualTo(results[i]), $"Mismatch at index {i}: expected {fileData[i]}, got {results[i]}.");


ooo you did it here. Nice!

dacharyc

Thanks for the comments and suggestions! Anything else jump out at you here?

dacharyc · 2025-07-01T15:48:32Z

usage-examples/csharp/driver/Examples/Aggregation/GroupTotal.cs

+        // :uncomment-end:
+        // :snippet-end:
+        var client = new MongoClient(uri);
+        _aggDB = client.GetDatabase("agg_tutorials_db");


FWIW, the DB name comes from an existing code example. This is the DB name used across 5 pages across all of the programming languages, so changing it would be non-trivial and out of scope of this PR.

dacharyc · 2025-07-01T15:49:44Z

usage-examples/csharp/driver/Examples/Aggregation/GroupTotalOutput.txt

@@ -0,0 +1,3 @@
+{ "CustomerId" : "oranieri@warmmail.com", "FirstPurchaseDate" : { "$date" : "2020-01-01T08:25:37Z" }, "TotalValue" : 63, "TotalOrders" : 1, "Orders" : [{ "OrderDate" : { "$date" : "2020-01-01T08:25:37Z" }, "Value" : 63 }] }


Just pulling it in from the docs page where it's currently used. We don't pretty format it there, so I kept the existing formatting. (Presumably because pretty formatting it would make it much longer, and that would take up a lot of real estate on the page, but I'm making an assumption.)

dacharyc · 2025-07-01T15:51:15Z

usage-examples/csharp/driver/README.md

+
+## To run the tests locally
+
+### Create a MongoDB Docker Deployment


It's a holdover from the other test suites - not specific to C#. But my recommendation is for us to test things locally unless Atlas is required, as local testing doesn't require spinning up cloud infrastructure.

dacharyc · 2025-07-01T15:55:03Z

usage-examples/csharp/driver/README.md

+   27017/tcp -> [::]:27017
+   ```
+
+### Create a .env file


Oh, good point. I've changed the way I'm loading this so it's now being used properly to load .env vars at the beginning of the test suite run instead of having to read the file over and over again in various places to get the vars. I think the third-party lib is justifiable for env var management, and according to NuGet, this one has 12 million users. I think it's probably safe in this case to assume it's reasonably maintained.

dacharyc added 5 commits June 27, 2025 18:01

Add PoC C# test suite

e06b5dc

Add handling for .env variable connection strings

ce6c4b6

Load output file from path relative to solution root

d25aa4c

Add README

e7026c3

Add Bluehawk markup

250229d

dacharyc marked this pull request as ready for review June 30, 2025 20:07

MongoCaleb reviewed Jun 30, 2025

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dacharyc commented Jul 1, 2025

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dacharyc merged commit f974707 into mongodb:main Jul 3, 2025

dacharyc deleted the csharp-test-suite-poc branch July 3, 2025 13:08

		@@ -0,0 +1,3 @@
		{ "CustomerId" : "oranieri@warmmail.com", "FirstPurchaseDate" : { "$date" : "2020-01-01T08:25:37Z" }, "TotalValue" : 63, "TotalOrders" : 1, "Orders" : [{ "OrderDate" : { "$date" : "2020-01-01T08:25:37Z" }, "Value" : 63 }] }


		## To run the tests locally

		### Create a MongoDB Docker Deployment

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